Colleges around the country are beginning to consider whether they ought to divest themselves of stocks in companies that produce fossil fuels. That includes Middlebury College, which is responding to the earnest prodding of activist Bill McKibben and students looking for ways to address the problem of climate change.

ExxonMobil is not likely to quake at the idea that a small New England college might dump a few shares of its stock, nor would the company’s stock price be likely to feel any tremors. But the new divestment movement represents the crystallization of an important idea: that the exploitation and consumption of fossil fuel threaten the planet. It calls into question the entire raison d’etre of ExxonMobil and other fossil fuel companies.

Around the edges of the climate question, people are taking steps — switching to efficient light bulbs, buying efficient cars, sealing up their houses. These are all important steps that slow the consumption of energy, crucial for curbing the production of greenhouse gases. But gliding, rather than plummeting, toward climate disaster does not solve the problem.

The energy companies are still in the business of producing oil and coal, and whether it is consumed at a rapid pace or at a slightly less rapid pace, the problem is the oil and coal. For example, Canada is exploiting the oil trapped in tar sands in Alberta, a quantity of oil that is said to equal the reserves in Saudi Arabia. NASA scientist Jim Hansen, one of the world’s leading experts on climate change, has said that if carbon from the Canadian tar sands is dumped into the atmosphere, then it is “game over” for the climate.

It is not a question of insulating our houses so we don’t burn oil so quickly. It is a question of not burning the oil. Ultimately, the way to avert climate disaster is to leave the oil in the ground. The same goes for coal.

It is easy to say that we should not burn coal or oil. But vast economic interests depend on those fuels. Driving through the Midwest, one encounters seemingly endless freight trains transporting endless quantities of coal to towering mountains of fuel at numerous coal-burning power plants. This is a reality far removed from Vermont with its burgeoning number of solar projects and wind towers and its efficient hydropower. Driving to any urban area, one encounters oceans of automobiles choking the freeways and consuming vast oceans of petroleum. None of this is going to be reversed by the investment decisions of a few colleges.

But paradigms shift. The movement to divest of stock in companies doing business in South Africa was derided as ineffectual and naive, but in the end it helped to cast the apartheid government of South Africa as an outlaw. Similarly, a more broadly held belief that investment in fossil fuel companies is not socially responsible would change the atmosphere.

The spigot will not be turned off in an instant, and there would be economic chaos if it were to be. Thus, development of technologies to minimize the harm of fossil fuels is worth pursuing. Meanwhile, efforts to call attention to the tentacular reach of the fossil fuel industry also expose the dimension of the problem.

For example, a pipeline reaching from Maine to Montreal, across northern Vermont, has become a concern for activists because they fear it will be used to transport tar sands oil from Montreal to Maine. Environmentalists worry that the pipeline might be subject to spills, but the real concern is the oil itself. If the primary aim is to keep it in the ground, allowing its transport to market runs counter to that aim. The same issues have stalled the development of the Keystone XL pipeline from Canada to Texas.

It’s not easy for a college to divest itself of a particular category of stocks. Their portfolios, just like the 401(k) plans that many workers have, comprise numerous funds for which it’s hard to track individual holdings. But making a statement would be a first step in the effort to change our energy paradigm.